single electron transfer
(rus. одноэлектронный перенос)
— an intermediate stage of many organic and biochemical reactions characterised by transfer of one electron from donor to acceptor.

Description

This process is very common in nature. In fact, it is a redox process. The transfer usually results in a state with split charges: DA → D+A– (D — donor, A — acceptor of electron).

Electron transfer plays a key role in many biochemical reactions. For example, one of the critical stages of photosynthesis is the transfer of an electron through a bilayer cellularmembrane. The process begins at a dimer of bacteriochlorophyll (P) and includes a series of electron transfers from one substance to another (see fig.). The final electron acceptor is a quinine molecule (QB).

Illustrations

Energy diagram demonstrating transmission of an electron in reaction centers of purple bacteria. P — a dimer of bacteriochlorophyll that, when exposed to light, changes state into excited state P*, which makes it an electron donor. BChl — bacteriochlorophyll, BPh — bacteriophaeophytin, QA — alternate quinone, QB — electron accepting quinone. Electron transfer time is indicated for each stage.